DE3312723A1 - SIGNAL TRANSMISSION SYSTEM - Google Patents

Description

- 10 - U.Z. 876.6 '■ -' - ~

TELECABLE VIDEOTRON LTD. {■: ■■■■ ■ - ~ - 3700 Blvd. Losch ι- - ■ ·: St. Hubert, Quebec, G3Y 5T6 ·:. ·. : Canada

SIGNAL TRANSMISSION SYSTEM

The invention relates to a signal transmission system for delivery

of television, information and data signals via a transmission

- Network to several participants, and especially for the > -.- Be ::::: ..: ■ ·. <;:. :: · ■. ·.: '., .-

^ z &, division of such signals for selected participants,

Groups of participants or all participants who attend together

connected to the network. - ■

Information signal distribution systems such as cable television systems typically distribute television signals to their subscribers via unidirectional networks in a "star ¹¹ " or "tree" arrangement, although other network forms have occasionally been used.

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Drivers offered, such as ": two-way data transmission and distribution of data (e.g. TeletextsignaDe) to selected ones Participant stations. In the former case, Leituhgs were two-way amplifiers built in to signals emitted by the subscriber ^ e.g. Service requests, polls, banking, alarm messages, Goods orders etc.) to the central station of the cable distribution system on a predetermined frequency band / and in the latter case, data can be sent to subscriber stations having predetermined electronic addresses ....

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However, it has been shown that the costs for subscriber stations with predetermined functional capabilities, e.g. the ability to to download a video game program, the ability to call up various levels of information and data services, the ability to share a coin-operated television folder, the ability to reach certain normally inaccessible television channels are relatively high. If a participant ■ merstation is equipped with the minimum range of functions. the participant receive additional plug-in modules that give him the lend additional functions if the use of the station is to be expanded, or the cable distribution company must send a maintenance man to the subscriber to install the equipment required for the additional functions. In addition, such systems can be copied by black listeners who would be able to manufacture and add modules that allow the subscriber to access programs or data for individual purposes without the control of the Plant operator and to receive without payment.

.

The invention allows a relatively cheap subscriber station to create, thereby enabling the station to be able to perform additional functions under complete Control of the system operator 'to receive and without

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require maintenance by service personnel ..

The invention creates a system in which the information required for converting or decoding, data and other signals transmitted by the central station is output by the cable distribution central station (down-loaded) which can change this information, which is still to be described, at any time. The ability of the subscriber station to collect data is thus under complete control of the ■ plant operating company. The ability of the local subscriber to receive data can be changed at will by the cable distribution central station. Program that is issued or can be used to control certain devices in subscriber stations such as, for example, coin-operated television files, channel converters, audio frequency attenuators, etc., can thus be sent to all subscriber stations, but can only be saved by those to whom it is addressed

■ was. A control program can be output to selected addresses which consists of a table of options, e.g. the reception of certain programs or services and the Control of certain channels with the exclusion of other

- equips. These programs can be done from the central station like this changed often as required.

As a result, to prevent unauthorized access to certain Data signals from the cable distribution central station the code keys required for reception at intervals "changed by seconds, hours, days, etc. and thus the unauthorized Access can be suppressed. The code can be changed at regular intervals or as required, and the individual Of course, address changes do not need to be made according to an easily understandable scheme.

This facility allows the cable distribution company

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also, certain selected "" information to selected groups

■ -. To send ''"-pen example, if to a group of physicians medical ~~ information in certain regular Abständen.empfangen who subscribed doctors would receive a predetermined Empfangscade The .empfangende to information, for example, would be transmitted as data signals. , would be sent to all cable subscribers, but only those doctors with the special code stored in their service option table would be able to receive it.

If in addition a single member of the group additional If you want to subscribe to services or cancel the special option, a new code can be saved to identify the Updates the right to receive certain types of signals.

Each subscriber station can choose packets that have three types of addresses: a global address (intended for all subscribers), a service address (determined by the

ZO . special services that are made available to individual subscribers), and a subscriber identification address that is intended for a specific subscriber. The latter address code is stored as firmware in the subscriber station, which is contained in the device of the subscriber station in an integrated circuit adapted to it, which can be installed during manufacture or at any time. This predetermined subscriber identification code is kept by the cable distribution company and is used as an identifier when storing the information signals for the service data in order to allow the local subscriber to access these services. This function will become apparent upon review of the following detailed description of the preferred embodiment of the invention.

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.. "" Each transmitted data packet corresponds to the form of a first encryption level - the use of special additional bits such as occupied bits, filter bits, etc. can make your data packet "unusual" for a potential fraudster. Give appearance, ie aa: i stealing the signal, ^ heavy.

Although a cable television system is described here, is to Note that the transmission medium is not limited to coaxial cables! is, but that the medium is a fiber optic SigE & al distribution system, a satellite system etc. can be. The same is true of the system described as unilaterally directed preferably used in a bidirectional system.

Generally speaking, the invention is a signal transmission system with a central station, one with the central station associated transmission medium for -the transmission of signals from the central station, a number of with the transmission medium connected subscriber stations and with devices in the subscriber stations for receiving and storing signals from the transmission medium, 'which are indicative of the predetermined station addresses. Further devices in the subscriber stations, the station addresses for receiving and storing from Have stored program signals from the transmission medium, which are only indicative of subscriber stations, at deneia ■ certain station addresses are saved. Other devices in i * 3s- the subscriber stations that have some of the option codes, are for. ^ the reception of further signals from the transmission me- dium and designed for the implementation of these additional signals, the implementation of the previous storage of the Depends on program signals.

■ In particular, the subscriber stations contain a device for storing a first predetermined address code signal _¥ a device for receiving a second predetermined option code

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.signals from-the transmission medium as well as for storing it, a device for receiving and storing a signal nals, which has an address part indicative of the first or second code signal, a device for converting the the latter signal in the event that the address part matches the first .and second code signal, whereby the operation of the subscribers ^ merstation is released on the basis of the same:

• The transfer device preferably contains a device for enabling the subscriber station to convert further signals into one prescribed by the latter signal When the subscriber station receives signals which contain an address part which is indicative of the first or second code signal exhibit.

The. The invention also relates to a subscriber station for connection to a transmission medium for controlling the conversion of signals from the transmission medium for transmission to a A display device which includes a device for storing the conversion control signals received from the transmission medium which are addressed to the subscriber station, "as well as a device for converting from the transmission medium sent signals under the control of the control signals, the conversion control signals are preferably stored in an option table memory stored in the subscriber station.

In particular, the subscriber station comprises a demodulator for connection to the transmission medium for converting the digital signals sent by the transmission medium on baseband, -ein Data acquisition circuit for receiving the baseband digital signals and their transfer to the bus system, a first logical address memory for permanent storage a first address code signal connected to the bus arrangement is a second random access memory to the

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Storing an operation code signal as an option table, the is connected to the bus arrangement, a third random access memory that is connected to the data acquisition circuit .und the Bus arrangement is connected, for storing control signals, an input / output circuit, which is connected to the bus arrangement and has several input and output control connections, as well as a F.erns eh signal folder with an input to the connection to the transmission medium in an input current path, an output for connection to a display device in an output current path, and a control input which is connected to an output control connection of the input / output circuit, a processor connected to the bus, the folder being shared when the processor generates an "order signal that applied to the input / output circuit under control of the control signal.

In a further embodiment, a display generator is on the bus arrangement for generating alphanumeric / alpha-geometric characters and / or structure signals under control of the processor according to the control signal.

Exemplary embodiments of the invention are explained in more detail with the aid of the figures. It shows: · '

"Fig. 1 is a block diagram of a signal distribution system, under Use of the invention,

"2 shows the data format of the signals sent in the system using the known line procedure for Large-signal data control "(HDLC protocol),

3 shows a block diagram of a subscriber station,

3A shows a table for a preferred form of memory allocation;

3B is a flow diagram for the preferred startup sequence;

Figure 3C is a 'preferred sequence for loading' flowchart ...- '"' -" of a temporary software module, "5 ■. '

Fig. 4 is a block diagram of a data demodulator for. Use in the subscriber station,

- Fig. 5 is a logic diagram of a circuit which certain- · Branches off these signals for transmission to a data acquisition circuit,

Fig. 6-8 Logical circuit diagrams of various parts of the participant

merstationj
1.5 "'·

Fig: 9 is a block diagram of the control unit and its interfaces, and

10 is a circuit diagram of the cable interface circuit. 20th

In Fig. 1 a cable network is shown using the system according to the invention. A familiar one or two directional coaxial cable ferries distribution network 100 in tree shape has a number of subscriber stations 101 connected to its branches. One of the subscriber stations 101A is shown in greater detail to which a television set 102 and a push button remote control device 103 are connected is. The television set 102 provides a display for the subscriber, and the push-button remote control device 103 is used to control de Coin-operated TV folder for selecting channels from a channel converter and, if it is a bidirectional system, for sending commands or response data to the central station of the cable network. ".--" ·

The KabePi distribution central station is connected to the network sen and consists of a control unit 104, for which various signal inputs are provided. On a cable television distribution network According to the state of the art, the control unit 104 would consist of a multiplexer for outputting several signals to the cable.

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. - Stands that represent television channels, with one or more "." —Channels could be coin-operated television channels used by the subscriber need to be decoded.

At. the system according to the invention, however, receives the .Steue.r-

- "If 104 the television channels are transferred from a television signal as before

^: source 104A and bundles them with data signals, which are preferably carried in one, but possibly more than one "6 megahertz wide otherwise unused channel. It should be noted that" the data signal width of 6 megahertz 'is selected "became ',' because it is the bandwidth of a single television channel - ^: 'where it can be, for example, channel 14th or any other channel · in the middle or upper band range of the channel series or a frequency and bandwidth that cannot

Vf? bel ^ broadcast interferes with television broadcasts. ■

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The data channel transmits data signals, mainly from information and control data exist, but with partial communication signals, with signals that deliver certain "services" to the subscriber, with test signals, computer sp'id-isignalen, Participant dialogue signals etc. are bundled, the "- where" "forms each signal in a predetermined way to be described und'by an address for subscribers TDestämm ^ willv 'for the receipt of such services

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The information and data to be transmitted are stored in a large-scale writing access memory (preferably a hard disk memory system) in the control unit 104 and are sent again over the cable. In the preferred system, 20? ÖÖ'Ö ^: "Pages with an average of 500 bytes per page are stored in / in memory and sent repeatedly over the cable, f'iOOO pages per second at a rate of approximately 4 megabits per second.

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The - information is supplied from one of several central data sources 105 with devices that either locally (NE ■■ "ben control units 104) or can be housed away, and they are by transmission lines, a directional) radio communication, etc. empfangen.- The data can thus be loaded into the memory of the control device 104 from the remote location by reading in the data stored on tape, disks or the like, which data is formed on the spot or elsewhere.

In addition, a service computer 106, which is operated by the operator des Cable distribution network is operated, connected to the control unit 104 and contains an input keyboard 107. On this The local cable operator can enter new operating data into the local computer 106, which converts the data into signals • converts, which are fed to the control unit 104, whereby changes in the entitlement to services according to "the operator Instructions given on the keyboard can be provided to participants. The control unit 104 forms automatically the operational information and that from the central data source delivered data and transmits the formed data either repeatedly or in individual transmissions in asynchronous Packets that contain coded prefixes in which it is specified which class of service subscriber stations can implement the data. The resulting system enables

I ^ it is normal cable television for all cable television participants and allows those subscribers who have paid for the coin-operated television to keep their local stewards up and running to put. The system also allows the cable network

ü operator, predetermined information data signals to all participants and to transmit certain information to predetermined subscribers, which are identified by company addresses (class of services) be identified. In a unidirectional distribution network, such predetermined data are repeated over a predetermined period of time, e.g. one day or several

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_Days, sent; a bidirectional network, on the other hand, would be a local ■ - "' "Borrowed subscribers give the ability to transmit predetermined '" data signals to request to him (provided that he is authorized to receive these requested signals), by pressing the corresponding pushbuttons on the remote control unit. ■ -. "

The data signals are transmitted from the control unit 104 in the extended address format of the standard large-signal data control, which "is shown in Fig. 2. Additionally, as part of a collision avoidance facility for two data signals transmitted in the direction of the central station. Information bits (referred to herein as "busy bits") which after receipt of any signals sent in the direction of the central station by the controller 104. the state of the Central station directed channel determined.

• The two occupied bits enable the display of four "loading

Laying "states: free, occupied, collision detected and Priority. Although this aspect does not form the essence of the invention, it should be mentioned that the occupied bit in the central station subsequently inserted into the data signal after a marker byte (at both ends of each packet or between the packets) and still all 64 bits (although any other format could be used if so desired-P ^ _ is worth seeing.)

The signals are sent in the form of asynchronous packets, the horizontal axis being the signal formation shown in FIG from left to right denotes the time. As mentioned before, the bits are transmitted at approx. 4 megabits per second, preferably with NRZI modulation on an HF carrier wave with the desired transmission frequency.

According to ~ the GrolSsignal data control line procedure with extended Address, the first byte is an identifier byte, followed by four address bytes'. In the "preferred embodiment of the invention" the first two address bytes identify the digital channel number, and the second two address bytes designate the rare number. This is followed by a control byte. To the control byte is followed by all "information bytes. This could e.g. Represent 6,400 bits that would be required to e.g. a display page which is 40 characters wide and 20 lines long, with each character having a length of 8 bits.

The information bit is followed by a block check character string FCS, which, as is well known, is a series of bits which, together with the remaining bits between the characteristics, form the solution of a polynomial deliver, the remainder of which is 0, and which is used to search for transmission errors. The FCS bit is followed by an identification byte.

The signal packet described above also contains the aforementioned allocation bits and "zeros" which are used where otherwise a series of six "ones" could appear. Conventionally, a series of "ones" denotes a termination, which indicates that the contents of the packet at the subscriber station not to be taken into account is.

• Apart from the allocation bit, the S ^ described above is followed. Package contains the recommendations of the CCITT standard X.25, which are laid down in the international standard No. IS03309 with the designation "DATA TRANSMISSION - METHOD WITH LARGE SIGNAL DATA CONTROL - BLOCK STRUCTURE".
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The packets can be formed in the control device 104 in a known manner will.

Fig. 3 is a block diagram of the preferred form of the partial

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-nehinerstation, which deals with the "data reception from the central station concerned with the subscriber station. The signal from the cable junction is received via the .Klemme 301 and sent to the Down converter 302 applied. The down converter 302 is a television channel converter, the enable signals and switch- - Receives error signals from Bus.303.

The step-down converter -302 preferably has three outputs, a video output on baseband and two audio frequency outputs,

.10 about television with stereo sound, music, radio signal reproduction, etc. to enable. These signals are fed to folder 304, of which an enable input is connected to bus 303. Of the Folder 304 can be of any known type and, for example, allow normal signals to pass, but only order scrambled signals and pass it on when it receives a release input signal at its release connection. If "is preferred, L-j an order code can be supplied to the folder 304.

The audio frequency signals from the folder are voltage-controlled Attenuator 305 is supplied, the output of which is connected to .ein input of the television modulator 307. The voltage controlled Attenuator is terminated on a control bus 306, the one with an output connector to be described connected ". The output signal of the attenuator '305 is connected to an input of the modulator 307.

The baseband video signal from folder 304 is fed to the display generator 308, whose, output with another , Input of. Modulator 307 is connected. The output of the modulator 307 is connected to an RF connector 309, and the The output of the visual display generator 307 is connected to a base , band-RF connector 31Ό connected.-When operating the 'described above Both normal and scrambled television signals are used as well as HF-modulated data signals at terminal 301

received and converted to baseband in downconverter 302. ■ The frequency to which the down converter responds becomes set by a control signal received from the input / output (I / .O) connector circuit (which is still to be described) is received, - the at main address-. and control buses of the subscriber station connected.· · -

Ordinary television signals are passed through folder 304. Scrambled signals are only used when the Ord-. ners that is released by a signal that is on its enable input and from the input / output port circuit Will be received. If no operating data signal of the corresponding class is stored in the subscriber station is, the I / O port does not share folder 304, likewise, downconverter 302 does not operate if not Operating data signal of the corresponding class in the subscriber station is stored. Since the operating class signal is sent from the central station to selected subscriber stations the central station can control the use of the down converter and folder services .. ·.

As already mentioned, the audio frequency outputs are from the folder 304 directed to the voltage-controlled attenuator 305. The attenuator 305 also has "a control input to which . the line 306 is connected and at the same time connected to an output of the input / output connection circuit. Consequently can data that are present on the address, data and control buses of the local subscriber station (and at least can be partially under the control of the local subscriber) for attenuating the audio frequency signal to baseband be used. The audio frequency signal can of course be fed to a local loudspeaker if wishes. In addition, there is an input / output-output connector 311 connected to an input of the attenuator 305,

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thereby providing data bit outputs from the input / output port circuit _ can be fed to the attenuator as an audio frequency output. According to this, the participant can use synthesized music, transmit synthesized speech, display tones or the like 5 · telt. ,, _

The output signal from attenuator 305 is sent to an input of the modulator 307 placed. At the same time, "the basis". tape video signal from folder 304 via the display generator.

"10 308 is fed to another input of the modulator 307. The Modulator 307 modulates the video and audio frequency signals onto an RF television carrier frequency, e.g., typically on channel 3 or 4, and delivers the resulting signal to the HF connector 309 for feeding into the antenna input of a standard

-15 dard television set. Optionally, a video monitor for receiving the baseband video signal to the RF connector 31 ¹ O, can be connected.

Attached to the display generator 308 is a random access memory RAM 312 connected in a known manner. The display generator 308 is connected to a local bus arrangement, which consists of an address bus A, a data bus D and a control bus C. As a result, signals from the A-Bus, the 'D-Bus and from the C-bus (hereinafter referred to as the ADC bus).

'■'"_" - * -. The signals received at terminal 301 are also applied to the input of demodulator 313. The demodulator 313 provides clock signals, data signals and identification signals to a data acquisition circuit 314 which is also connected to the address bus A and the control bus C. A dynamic random access memory RAM 315 (typically with a nominal capacity of 16,000 bytes) is connected to a three-state buffer 316 which in turn is connected to the ADC bus and data acquisition circuit 314.

A 'raw input read only memory 317 is also with the ADC bus - '"" "connected, there is also an option table CMOS free access memory RAM 318, im. typical case with 256 bytes in groups of B bits, connected to the ADC bus.

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\ kn the option table CMOS random access memory RAM 318 is connected to a large capacitor 319 (e.g. one Farad) which is charged by a local power supply (not shown) and maintains the operating voltage for the CMOS random access memory in the event of a power failure in a known manner to ensure data storage. ''

A programmable read only memory (PROM) for logical addresses 320 is also connected to the ADC bus and can be integrated into another circuit such as the data acquisition circuit (to be described) or the central computer. Likewise a baud rate generator 321 is connected to the ADC bus and to a peripheral bidirectional connection circuit 322, which is also connected to the ADC bus. The peripheral connection circuit - 322 has a number of input and output terminals, e.g. to create an output bus format for RS-232 line procedure (RS-232 protocol output bus format), a TELIDON format, a printer interface, a microcomputer interface etc., via the input / output lines

323. ■■ '■■ · .- *

Γ * "- A local central unit CPU 324, e.g. of the type MC6809 also connected to the ADC bus.

An input / output (I / O) connector circuit 325 to the far referred to above and which operates down converter 302, folder "304, attenuator 305, etc." is also connected to the ADC bus. An output of the input / output terminal circuit 325 is connected to a relay circuit 326

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- connected for the operation of a power output 327, _and ^ e.in input of the connection circuit is on. an infrared interface 328 of known construction-connected. An infrared sensor diode is attached to the infrared interface 328 329 for receiving infrared pulses from a • Remote control device connected. Of course, an infrared control does not necessarily have to be used, as the Remote control device also via a cable or an ultrasonic connection. Binding etc. switched to the connection circuit 325. - can. · "

It is assumed that someone who understands this invention is sufficiently qualified, so that a detailed description the operation of the central unit in connection

^; it-5 tion with rden different to be described peripherals "-a th superfluous here and in view of the disclosure herein of the system structure and the algorithmic description 'of the interaction of a repeat represent • would; -Die- the ADC bus supplied and from the central unit

22.0 ■ honored. Data signals can pass the down converter 302, the. Folder: -50.4, "-; control the attenuator 305 and the relay 326 via the ^: n input / output connection circuit 325 -received. Data signals via the Eih-ZAusgabe connection. SaHision i325 is led to the ADC bus and from the central unit: · .. processed '. '. ·. " ^: ■ '·. ■'. ·.: ... '\, ■ -":.; T, - ^; . \ -. 1 -, - 1is the Tei ^f ne;: .. t;. : "..'.-. ■ .-.;.: _ :. ■ · ..: .. ....- .. '■". l: ... i.

The following description, however, deals in detail rinit: the operation of this circuit, whereby it sends data signals from

; 3'0 Käbelrietz-ibenötigen that one. Contain address which. ::. ζ, which denotes the local subscriber device. The structure of this si ÖörätS- ,. ttei-which the address can be changed at any time '- ^ n and ^ de'ssen' information content (option table and operating programs) can be stored under the control of the central station to the subscriber (down-loaded) is considered special

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considered useful feature of the invention.

As already mentioned, the four bytes immediately following the first identifier in each data packet contain the Address bit. There are preferably three types of address " sen, a logical address, a total address and an operating address. The first two bits of each address are used to indicate which of the three address forms follows. The logical address designates a specific participant, the overall address designates all participants, and the company address refers to individual participants whose addresses correspond to certain services. '

The "logical address that designates each individual subscriber station, is stored in the programmable read-only memory PROM 320 for the logical addresses are stored. This address is ..from Cable operator established and is integrated into the appropriate Switching of the station installed or programmed in before the device is set up - The option table memory 318 contains the company addresses, which are saved as data to be saved under the control of the local central unit. CPU 324 for the participant are stored (downloaded) and in a still to be described in detail Way to be made available.

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The total address is a wired address and is fixed as such. The overall address designates all participants, which are connected to a certain distribution branch. The "total address" can be used in interactive operating systems e.g. for electronic mail delivery etc. , · ■ where the control unit of the central station needs the communication of the address of a certain distribution branch, whereby all subscriber terminals can be taken up.

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- "'The original input non-volatile memory ROM 317 contains only enough firmware, v / are to operate the central processing unit for 'controlling the To enable operation starts and the storage of the original control signals passed by the cable for storage (down-loaded),,. from the control unit of the central station

* to be transferred and for this individual. Participants correct and picked up by the data acquisition circuit 314 will.

"Therefore, prior to startup, the free access memory contains 318 for the option table does not contain any valid data, the programmable read-only memory PROM 320 for the logical addresses contains the logical addresses for the identification of the participants, the original input read-only memory ROM 317 contains a start-up routine, and the random access memory RAM 315 does not contain any valid ones Data. . '. ~

"The ROM 317 original input read-only memory should also have enough stored Contain control signals, e.g. to the central unit CPU 324 for controlling the input / output connection circuit and thus to enable the step-down converter 302, whereby the elementary television channel converter operation can be carried out. After startup, additional control signals are stored in the free access memory RAM 31'5 stored, whereby an improved converter operation for coin-operated television, folder operation, information, Computer-aided games, software services, arise if the participant has paid for these services. ·

A data packet is sent to a logical address, welehe determines the operating address for this subscriber station, as well as codes which several subscriber stations have in common to whom the same types or classes of service to be delivered. The service may consist of coin-operated television that certain forms of

Information or data picked up and a "visual --- show can be brought, etc. The operating address data is loaded into the option table memory 318, stored and by the "charge protected against power failure" stored in the capacitor 319.

Of course, the entirety of the free access memory can be saved as a a single material unit can be built up. ,

D A preferred form of the data acquisition circuit connected memory is shown in Figure 3A. The memory is divided into a DAC buffer, a waiting list buffer, Storage space for the down-loaded software from the central station, storage space for input / output software, an option table section, additional space for input / output software and the read-only memory section (ROM). .,

3B and 3C are flow charts showing the operation during the start-up phase and when loading a temporary. Software module (referred to as MTO) show (downloading) from the central station, which enables the device to perform the pass on the rest of the software for storage (download).

The startup phase begins after a hardware reset, the due to a power cut or initial installation. At this point in time, the memory contents are with The exception of the permanent storage is invalid and the software to be executed is contained in the permanent storage. The hard drive should Contain temporary interrupt vectors, in particular those of an interrupt request for the central unit. The software contained in the permanent memory for the start-up first defines the start-up and blocks all address comparisons the data acquisition circuit (hardware to be described), and thus interrupts any further acquisition. She loads in

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- d'ie data acquisition circuit the packet address obtained from the "__" digital channel number for storing (downloading) the software and consists of side 0 of this channel. It then waits in a queue until page 0 is received correctly 5. and "actuates the automatic reset of the central unit.

Data packets are sent from the central station via the logical address sent. Upon receiving everyone. Package, the data acquisition circuit checks the data in a (still referenced on Fig. 8) CRC circuit to determine whether the packet is error-free and whether the line procedure is also it's correct. The information field of the packet is then transferred to the buffer for the waiting side. At this time the acquisition is completely controlled by the central unit, and there is no risk of the acquisition circuit overwriting the memory during the transfer. The received software must nevertheless be transferred to a suitable temporary area, but preferably outside the active memory area, in which the further storage (downloading) of the software is to take place.

This first received software package is a preliminary software module (called MTO), the purpose of which is to provide the Save (download) the rest of the software. At this point the execution of the start-up ends. phase with a jump to the first command of the MTO module in Buffer for waiting times.

As can be seen from Figure 3C, the MTO software checks first the validity of the existing option table. This table is contained in the free access memory 318, which protects against power failure short or medium duration by capacitor 319 is protected. The data comparison check is carried out in a manner to be described with reference to FIG. 8.

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IrcuIf the first installation or a longer power failure is ■ - * there is the fact that the option table is invalid. Irt this case the MTO enables the comparison of the logical address of the data acquisition circuit (at the same time the check the total addresses and the operating addresses are blocked. ) A simple message such as a blinking cursor should be in an outbound device such as a Television terminal are displayed, which is connected to terminals 309 or 310 is connected to indicate that the interface is on. waiting for an option table to be received.

If the circuit is either a new system or if a there has been a prolonged power failure, from which the central station Has knowledge, the required data page (s) will inserted into the digital channel cycle by the staff of the central station. Otherwise the participant has to agree contact the central station for its options table to get in order. In the case of a bidirectional interface the option table would be requested automatically via the return channel.

After the option table package has been received, it is sent again is checked and placed in the correct location in memory as shown in Figure 3A.

The option table contains the page numbers related to the

'' ** " . digital downloading channel. With these page numbers the acquisition addresses are formed by combining the number of the digital channel and the page number of the desired software module. This package address is then loaded into the" operating address register of the data acquisition circuit ( down loaded) ..

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The MTO software module then begins a loading loop, the consists of the following steps:

1) Reading the next page number in the table, 2) Formulating a new page address,

3) Load this address into the data acquisition circuit and Approval of the company address comparison,

4) After receipt and data comparison check = return to step 1 of the package.

As often as the packet is transferred from the buffer in the data acquisition circuit to a memory location next to the previous one. , v, only the usable parts of the packet are transmitted.

Finally "execution jumps from the first command received Software 'and normal operation begins.

The data acquisition, which sends the data signals to the ADC bus for operation according to the algorithm described above will now be described. The data acquisition exists from the recognition of the license plate, the address comparison, Kullen removal and checking for errors, as well Transfer of the data signals to the ADC bus. .. ·

In Fig. 4 the data demodulator is shown. The signal generated in the central station is received on terminal 401 (which corresponds to terminal 301 in FIG. 3) and fed to the filter 402. The filter 402 preferably has a high frequency passband between 30 and 300 mHz, and the transmitted signal coming from the cable reaches the directional coupler 403. The signals to be transmitted to the central station in the case of a bidirectional system are received on the line 404 and through a low frequency passband of the filter 402 via the 'terminal 401 on the cable

.. guided. The pass band of the low frequency part of the filter 402 can be specifically tuned to the feedback channel, which is typically in the range between 5 and 35 MHz. Of course, each part of the filter can be designed separately, and in the case of a one-way filter from the control center Structure, there are no signals in the direction of the control center, and therefore no low-pass part of the filter 402 is required to be provided.

_. An output of the directional coupler 403 is connected to the down converter 302 (Fig. 3) to provide the television signals; it will have to be described in more detail. The other output of the directional coupler 403 is to the input of one Demodulator 405 is connected, in which a signal after level adjustment and impedance correction e.g. from channel 14 with A central frequency of 120.016 MHz is converted to the intermediate frequency (e.g. 45.75 MHz), demodulated, automatically in the Gain is controlled and applied to a threshold detector 406. The threshold detector 406 should be a hard onset Limiter included, whereby the interference voltage in the output signal is suppressed. The output signal is on . The clock regeneration circuit 407 and applied to the sampling circuit 408. The clock regeneration circuit 407 is preferred a phase-locked loop. Since the data in each packet is preferably formed in NRZ form (without returning to zero) the sampling circuit 408 is preferably an NRZ detector.

The output of the clock regenerating circuit 407 is a T _a ktsignal H, which is derived from the supplied signals from the central station, and the 'output of the sampling circuit 408 is a data signal D.

It should be noted that the output signals of the control unit

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331272

in the central station consist of data packets of variable length and also of a variable time from one another are separated. Preferably should'the mutable Time to be filled in with identification bits. Therefore, even if the packets are transmitted asynchronously!

Synchronization of both the packets and the interim between. the packets with respect to the individual bits.

The circuit shown in FIG. 5 recognizes the characteristics and 1.0 clears the zeros which, as previously mentioned, are inserted according to the line procedure for "large-signal data control" to distinguish normal signals from abort signals. The data output D in Fig. 4 is applied to a shift register 501, and 'the clock signal H is applied to the clock input of the same Shift register applied. An inverted clock signal - H results from the clock signal H after passing through a Inverse circuit 502. · '-'

When the input signal is introduced into the shift register 501 on the data line D, two adjacent '. These are applied to the inputs of the AND gate 503, which is enabled, and its output is applied to the reset input of the bistable flip-flop 504 25 / Will / The clock signals H are applied. the clock input of the bistable multivibrator 504 is applied. Thus, if a flag "has been received, a high level output is present on the Q line of flip-flop 504 which represents a flag signal. - :, ·. ·· - ~ - 'represents the sixth bit position of the input data bits also the outputs A and C of the shift register 501 high. The AND gate ^: "ter .. 505 is then released, the output of which is inverted in the inverter 506 and connected to the residual input of the

., - bistable flip-flop 507 is applied. The Q output of the The bistable trigger circuit 507 is applied to the data input D of the bistable trigger circuit 508, its Q output becomes fed both to the clock input of the bistable multivibrator 507 and to an input of the AND gate 509. That Clock signal H is also applied to the other input ″ of AND gate 509, and the resulting output of the AND gate 509 is referred to as the HZ signal.

. Thus, the sixth data pulse of the input signal represents the The output of AND gate 505 is high and the input of flip-flop 507 is low. This is made possible by the bistable Flip-flop 508 implemented in synchronism with H and thus blocks the operation of the AND gate 509 at the sixth bit

1-5 digit. The clock signal H can thus be at the sixth bit position " Ie does not pass through AND gate 509. The HZ clock signal is therefore in synchronism with the clock signal H, except in the sixth bit position, where it is not available. This Clock signal can thus be used to clock the rest of the data acquisition circuit can be used whenever a bit is present, except for the zero-fill bits.

Fig. 6 shows a circuit for checking the address of the received Signal. To understand their function, however, reference may first be made to a portion of Fig. 7.

A binary counter 701 receives the clock signals HZ with zero correction and provides binary outputs at its output terminals Q ^ -Q-g. Its clear input CLR is with the flag output 5 connected. As a result, the binary counter 701 is "zeroed" whenever an identifier is received and starts again with each subsequent HZ clock pulse to count. The outputs of the binary counter 701 thus count the data bits received following each identifier. [

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33-272

It is reminded that the identifier bytes between ■■ the packets are transmitted. Therefore, the binary counter 701 is continuously set to zero between the packets.

As can be seen from FIG. 6, the outputs QA-QD of the binary counter are connected to the address register 601. The address register 601 is a register in free access memory 315, in FIG. the logical and the operating addresses are loaded from the microprocessor, these addresses from the programmable Read Only Memory 320 and from the Option Table 318 (Fig. 3) has picked up. The data inputs of the address register 601 are connected to the ADC bus via bus 602 under the control of the write permission line WE from the .. microprocessor.

The address is loaded into a data selector 603 which has two outputs: Y1, which carries the operating address, and output Y2, 'which carries the participant address'.

The data signal D (FIG. 4) is applied to one input each of the three non-equivalent elements 604, 605 and 606. The total address is fed from a hard-wired circuit (a known circuit that outputs a 32-bit serial code, e.g. a shift register with parallel input and series output, in which predetermined parallel inputs are grounded), this signal being the total address of the subscriber station designated and. is applied serially to the second input of the antivalence element 604.

Output Y1 supplies the 32-bit serial operation address in the same way to the second input of the non-equivalence circuit 604, and the output Y2 of the data selector 603 supplies a 32-bit subscriber identification address code to the second input of the antivalence link 606.

- 37 ■ · - · ''; · .- · ~ ^: · ■■ - 33Ί 272:

Let us now consider the function of the antivalence link .604. Its output goes high when any of its inputs are high or low, but not both Entrances. Assuming the total address is identical to the supplied data, both inputs of the Antiva- ■ drain member 604 in the same condition; As a result, its output is low. This is sent to the data input of a bistable trigger circuit 607, the Q output of which is connected to the clock input of a bistable trigger circuit 608 is. The Q output of the bistable trigger circuit 608 is connected to the reset input of the bistable trigger circuit 607. closed. The Q output of the flip-flop 607 is connected to an input of the NOR gate 609.

Thus, if both the total address and the data are the same for each bit, it is due to the flip-flop 607 no data input signal -an. Hence, its "-Q" output is at low level and provides an input at low level for NOR gate 609. If all inputs of the NOR gate 609 low, its output is high.

However, if there is a difference between the inputs applied to antivalence element 604, its output opens High level and allows the flip-flop.

607 from the HZ clock with the zero-cleared clock signal is clocked. The flip-flop 607 changes its state, which leads to the fact that the flip-flop is clocked and changes its state. As a result, the bistable multivibrator 607 is reset to its initial state. Your Q output has changed its state, however, and supplies a high level input to the NOR ^ gate 609. Its output goes low.

The antivalence elements 605 and 606 work in the same way *

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In these cases, however, the operating addresses and subscriber addresses stored in the address register 601 are each assigned with the n non-equivalence elements 605 or respectively. 606 compared. As a result, the output of NOR gate 609 goes high when any of the inputs of NOR gate 609 goes low, indicating that an adaptation of the address signal on the data lines with either the total address or the operating address or the participant address has taken place. The output line of NOR gate · 609. which carries this message "address correct" carries the reference number 610.

The output Q _{E of} the binary counter 701 (Fig. 7) runs through the reverse circuit 611 and is applied to the clock input of the bxslfcabilen flip-flop 612 '. Its Q output is connected to one input of AND gate 613 with the output "correct address" of NOR gate 609. Since the -Q output of the flip-flop circuit 612 goes high every 32 bits, the output of the NOR gate 609 is passed through the '·. ^ AND gate 613 once every 32 bits, and when the output is set to Leitsang- '610, is high, the output of AND gate 613' goes high. . '"'>'■>

UCIi

It has already been mentioned that the address of the packet following each identifier is 32 bits long _ (4 bytes, of which ... 25 ^ each is .8 bits long). Thus, when the NOR gate 609 has an ^e-level output 32 bits after the mark ', ^{r: tr,} a high-level output at the AND gate 613 is a Anzeicöäen ^r DA ^ for that the address has been completed and richtig'ist. The line that carries this "" correct address "signal at the -3.0 ,, output ^ of the AND gate 613 has the reference number 614. ^:: '' ·

The Q output of the bistable trigger circuit 612 is connected to the reset input PR of the bistable trigger circuit 612 and also , connected to one input of AND gate 615. The other

The input of the AND gate 615 is connected to the HZ line, ■ and the output of the AND gate 615 bears the reference number HZE. The output of AND gate 615 goes high and. indicates that 32 bits have been received and counted (and that the address counts have gone through).

Now that it has been determined that the identifier has been received that the 32 data bits following the identifier are either the total address, the operating address or the subscriber address correspond, the circuit is now ready to receive and use input data on the ADC bus transmitted by the central unit. This is done by the circuit shown in FIG.

The data signal D is applied to the data input D of the shift register 702. The clock source HZ is applied to the clock input of shift register 702, and the "correct address" signal from line 610 in FIG. 6 is passed through the inverting Buffer 703 to enable the EN input of the shift register 702 passed.

Consequently, the shift register 702 is enabled when the line "address correct" at the end of the address test cycle (32 . Bit) goes high. The data input goes into the shift register 702 clocked in synchronism with the clock generator HZ. That

The signal is converted from series to parallel circuit in shift register 702 ″ and held in signal memory 704.

The count output Q of the binary counter 701 runs through the reversing stage 705 and is connected to the load input LD of the signal memory. 704. · This count output of counter 701 is stored in the Form supplied that when the shift register 702 is full is, its output is held in the latch 704. While the shift register 702 with further input data fills, the signa} memory 70 ^ i is finally released,

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to output its stored data on the ADC bus:

* The outputs of the latch 704 are supplied in parallel to the ADC bus 706, and the output enable input of latch 704 is connected to 'the output enable terminal of the centering ■ traleinheit connected via the .Leitung 707th In this way, the data to be processed by the central unit and to be saved either as instructions or as operating address data (options), or also data that are available either directly or after processing by the central unit via the> display generator should, from the cable

picked up. ,. ·

'Fig. Figure 8 shows the data check circuit. · The data input signal is applied to the CRC circuit 801. This known function solves a polynomial using the input data as "Binary number and provides an output signal * if the solution of the Polynomial has a remainder. This output signal is the

• Line fed to the data input. D the bistable

20 flip-flop 802 is connected. A jerk is on

the MR input of the CRC circuit 801 from the license plate indicator. created. As a result, the CRC circuit is reset, see above

'often a license plate is received. As a result, the Em-

• Patch the identifier to the polynomial solved until the next one Identifier is received, at which point the

Output on the .ER line zero. be. If it doesn't is, the ER line is high and causes a change in state of the flip-flop 802, · and the 'Central unit becomes a. Output passed indicating that the information in the packet contains errors and possibly should be disregarded.

The flip-flop 802 is clocked as follows. The "correct address" signal is sent to the data input of a

"N ₁ " Tm

■ _ 41 -

.bistable flip-flop 803 out, and the reverse signal of the license plate indicator is connected to the reset input of the bistable flip-flop. Consequently, the flip-flop 803 becomes active at the beginning of each received packet deferred. .As soon as the signal "Address correct" \ has been generated on line 610, a data signal is received from the "correct address" line of the flip-flop

803 forwarded. The bistable flip-flop 803 is of the Central unit clocked and supplies an input to the ΑΝΏΙ Ο gate 804. A second input 805 is .dem AND gate 804 ^ supplied by a clock source. The output of the AND gate

804 is with the clock input of the bistable trigger circuit 802 tied together."

Provided that the signal "address correct" has been received, consequently causes the second indicator display (at the end of the packet) to generate a clock pulse for the bistable Flip-flop 802. If the output from the CRC circuit due to the remainder of the • polynomial calculation is low, if the Q output of the flip-flop 802 is high, which is an indication for the central unit that all received input data are free of errors. But when there is a remainder, the flip-flop 802 changes its state and the central processing unit receives the indication that 'the' data are faulty '.

Regarding the central station, it was mentioned earlier that the Control unit 104 processes the data packets and sends them to the cable " network transmits. A block diagram of the control device and its interfaces is shown in FIG.

The central station is preferably controlled by a computer 900, e.g. of the 'PDP 11/34 type, which the' Digital Equipment ' Corporation offers; The main parts of the calculator 900 are made

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from a central unit 901,. 'a memory 904 for loading. Currency of the programs and with some buffer areas, a • hard disk subgroup 903 and a direct memory access' Circuit 916. All of these parts are connected by a bus 902, preferably from the "UNIBUS" (trademark), designated type with which the computer 900 is usually equipped. ■. ■ .. -

The disk connection device should be able to read quickly, for example with 4.6 megabits per second, since the system preferably sends data to the "UNIBUS" at approx. 4 megabits per second. should output. The capacity of the hard disk connection device should be at least 20,000 pages, with each r 'page containing an average of 20 lines with 40 characters each, each character with a width of 8 bits, i.e. a total of at least 128 megabits with additional space for formation data etc. ' - "\

The data to be transmitted to the cable network are processed by the computer-901 assembled in a buffer area of memory 904. The "• contents of disk storage 903 are continually rapid and repeated at -4 megabits per second in this buffer area; -. des 'Memory 904 read in. Interlinked with this data are. occasionally data from the computer 914 via the interface 913-2.5 received, which is also connected to bus 902.

The direct memory access circuit 9 "16 is connected to the cable interface circuit 917 connected. The cable interface circuit is connected to a 918 modem, the output of which is ..-- 3Q with. one. Radio frequency multiplexer 919 is connected to which one Signal source for .Rundfunk- and scrambled coin-operated television signals via an intermediate element 920 is connected. The out · The output of the multiplexer 919 is connected to a high frequency terminal for connection to the cable network.

, .- In the plate connection device 903 are through central connection. rate pages added or changed. Each central terminal device consists of an assembler control computer and a data source. These central terminal devices are generally divided into three categories, one of which is located locally, the other is located remotely and the third is a user interface for the formation of test signals, the Start-up of individual subscriber stations for newly approved services, etc. contains.
'■. ..

The first category, for example, is a data source that consists of a disk connector 907 and a local assembly controller 906, to the bus 902 via the interface 905 connected. For example, plate 907 can hold 100,000 pages or contains a small number of pages and is used to form new pages that are placed on the disk drive 903 to keep it up to date. bring.

In the second category, a receiver interface 908 is 20. connected to bus 902. This receiver interface receives data over a communication line from any of several remote sources, e.g. an announcement device for stock market information, a device for teletext information ■ (e.g. TELIDON), a remotely located pontic X25 etc. 'In the system shown in Fig. 9, data is sent to a remote location from a number of disk connectors 909 formed to store data under the control of a control unit 910. The control unit is controlled by a - Operator station 911 controlled by keyboard. The control unit 910 is connected to a transmitter 912, which is connected to a transmission medium such as a coaxial cable, a fiber optic or a radio link together with the receiver interface 908 is connected. · '·

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The third form of central terminal device is ζ.B ₀ the "existing service computer 914 of the cable operator to which a keyboard 915 is connected ₀ The keyboard 915 can be used to initiate the start-up or new service options, whereby it causes signals for generated the startup of the subscriber station and fed to the transmission medium.

The computer 914 maintains a record named and Addresses of participants, payment records, etc. and used to be used for invoicing etc. used. In the present system, the computer 914 contains two additional ones Information for each participant, the logical ^ 'address of the participant, which is unique for each participant, and an operational address indicating the option codes. These data are entered into the computer 914 via the keyboard 915. Data management systems for handling this facility are known and do not need any further details here to be described.

.

If a new participant is to be connected to the network, or if with a certain group of participants their operating addresses or option tables are to be changed, the operator gives the computer 914 commands which correct the addresses of the participants, and cause commands to be carried on bus 902 via interface 913 which cause the computer 901 to send one or more data messages for the start-up of a specific subscriber station to form or the company address or option table one or a group of subscriber stations up to date To bring stand. The message format is stored in a memory contained in the computer block 900, and can be of any shape the designer desires and that of the central unit in the subscriber station can be recognized. After the notification has been formed

. the data transfer from disk drive 903 to memory 904 interrupted and in their place the specially formed messages from the computer 901 to the memory 904 via the Bus 902 stored. After this process is completed, the rest of the data is read from the disk drive 903, which continues to do so cycles and reads at the preferred speed of 1000 pages per second.

The memory 904 is continuously from the circuit 916 with Di _t rektspeicherzugriff read, which transfers the data to the cable interface 917th The cable interface 917 forms the data into packets, adds identifiers, zeros and voucher bits if necessary, converts the data preferably into NRZI format and transmits the packets, separated by identifier bytes, at 75 ohms to the modem 918. Of course, in In a unilateral downlink network, modem 918 is a modulator.

Modem 915 modulates the data signal onto a carrier signal, e.g.

on TV channel 14, or on a signal with a center frequency of about 120 megahertz. This signal is applied to an input of the high frequency multiplexer 919, which also includes the other at a broadcast television system via the cable ^to: transmitting broadcast television signals empfängt-. The television signal carried by television link 920 * may also include a scrambled television signal received from folder 304

(Fig. 3) for those subscribers who have paid for a coin-operated television service.

Data from other sources are usually saved periodically assembled in the main board connector · 903. So can e.g. an information library (e.g. "100,000 pages) be stored in a large, slower access disk drive 907. At various intervals or on command different pages can be controlled by the assembler

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. control 906 via the, ·. Interface 9Q5 and the bus 902 can be loaded into the disk connection device 903. If they are then permanently stored in the disk attachment device 903 instead of other stored pages, the on disk. 903 stored pages can be read repeatedly as ■ already described. The disk drive 907 can thus be used to assemble new pages of the information cycle or other data, for example computer game programs, which must be made available to the subscriber's local buffer memory 315 for use by the local central unit for those subscriber terminals whose option table allows them Access to the data pages containing the game programs or the like is permitted. It will be remembered ■ '''that each page contains an option operational address corresponding to the code provided for those participants which have access to data included in the packet.

The information to be transmitted to the subscriber stations or other data can also be assembled at a remote location using those already described Devices. Two disk drives 909 are connected to a remote control device 910 connected. The controller makes it easy to assemble data on the drives under keyboard control 911. On command or continuously within the framework of a data link, the assembled data are sent from the transmitter 912 to the Receiver interface 908, where it is stored on disk connector 903 under the control of computer 901 will.

The periodic sequence of the disk drive 903 for loading data into the buffer area of the memory 904 as well as the access to this data through a circuit for direct data access can be achieved by conventional and known means. The operation of the 918 modem is merely the reverse of that

'35 high frequency part of the circuit shown in FIG. the

Modulation of a data signal in NRZI format to a high frequency ■ The frequency carrier signal can also take place in a known manner, as can the bundling of the high-frequency signal in the multiplexer 919 and the subsequent transfer to the cable 921. The cable interface circuit 917 will next be described with reference to FIG. 10.

The direct memory access circuit 916 is conventional Circuit for acquiring data from sequential ' Addresses in memory 904 and it is connected to bus 902 '. Bus 902 is preferably a 16 bit bus with the preferred form of computer 901, the PDP11 / 34 shown in FIG Bit data words works.

The data receiver 1001 receives the 16 bit words and transmits it to a silo register 1002 (FIFO) with at least 48 words. The output signal from the silo register 1002 is -dem The parallel / serial converter 1003 is supplied, which forwards the data to the data selector 1004 at 4 megabits per second.

The data are also fed to the CRC generator 1005, which stores the bits for the block check character sequence (FCS bits in Fig. 2) calculated to be inserted after the information bits in accordance with the ■ standard HDLC line procedure. The block check string is known to consist of two bytes of 8 bits each. '- _.

The serial data bits are also fed to the counter 1006-, * the one release output for an occupied bit generator 1007 after every predetermined number of bits, e.g., 64.

It is recalled that the invention works in bidirectional transmission systems can be used in which signals are also transmitted from the subscriber stations to the control center can. However, if two participants send at the same time,

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there would be a collision between the signals and the data received in the central station would be erroneous. Therefore As soon as the modem receives a signal in the central station, it immediately changes the status of the busy bits, which, as already mentioned, are inserted after each identifier and then after each 64 bits. Consequently effected the 64-bit counter 1006 generates two occupied bits after each 64-bit of those supplied by the parallel-to-serial converter 1003 serial data. The output data signal of the busy bit generator 1007 "is also supplied to the data selector 1004".

A 1-byte (8-bit) identifier generator 1008 continuously generates identifier signals and transmits them to the data selector 1004. "'■""^;".'"""' ■, ^- '■■ -: i: .'- V-- ::'" "/

The output of the data selector “1004 is applied to a zero control circuit 1009 which generates a zero bit · ^r every five ones according to the HDLC line procedure. ¹ As mentioned, the generation of six ones indicates that“ a ". Correct packet not taken into account" will be " ¹ BoIl" * (which is referred to here as the abort signal). An input of the zero control circuit 1009 means the presence of "a * flag, or that an abort" will take place .soil which suppresses the generation of zeros. '"''/";>:; --- ■ --- _"; ^V._; v"V.;

The output signal of the zero control circuit 1009 is applied to the input of an NRZI encoder 1010, whose output is connected to a TTL / 75 ohm converter 10Ϊ1 ·: "The output signal of the converter 1011 is fed to the modem 918, its output is connected to the high-frequency terminal; 921. The Modern 918 contains a decoder for the information received from the cable ^ 'de ^ indicates ^ that with a, ■. the "modem ^ iÖ has a data outlet;": " ^: corridor, the * to the: receipti: bit generator; tor ^: " lOÖl ^:: returned ^; will/

127-23

which causes the status change · of the busy bits.

As mentioned, four states are described with two occupied bits, Channel free, channel occupied, collision detection: and priority. The output bits of the busy bit generator 1007 would thus be received by modem 918 after a Carrier signal from the "channel free" state to the state Skip "Channel busy".

• 10 It is the function of the data selector 1004, the data packets. . · To form, consequently two inputs, A and B, are used to set the format, which allows the choice of one of determine four inputs. First the output byte of the license plate generator 1008 is selected (input 00), then This is followed by two occupied bits from the occupied bit generator 1001 (input 10). This is followed by the " 1003 (input 01) received data, which contain the addresses with the following information bits. after the Information bits have been fed to the output of the data selector 1004, the output of the CRC generator 1005 is selected (Input 11), followed by an identifier byte from the identifier generator 1008. After '64 bits, however, there are two - Bit from busy bit generator 1007 switched to the output, with the busy bit code from that received from modem 918 Signal is set.

Of course, in the case of a unilateral from the central station to the subscriber-directed system the occupied-bit generator 1007 and the 64-bit counter 1006 deleted jDder . 30 can be set to zero.

The timing of the data selector is controlled by the sequencer 1012, which selects which of the inputs of the Data selector 1004 is selected. The sequence control 1002 is under the control of the main computer 901 and is

with this via the sequence control signal driver 1013, the Sequence control signal receiver 1014 and the bus 9Q2 in connection. The generation of the packets is thus under the complete control of the computer 901:. ■

A system was described that would make it possible for the operator of the Network enables complete control over the services to keep, which are made available for the participants connected to this network. The system can be used in one existing cable television transmission network used and can be set up in various stages of expansion to provide increasingly sophisticated services that the market development brings with it. For example, if the "-" "Participant stations are set up, can be the first option in the ordering of coin-operated television signals and / or the provision of special radio television channels for "selected partial" subscribers exist by establishing options which allow access to these channels through the television signal channel converter allow in the subscriber station. Groups of special participants such as groups of doctors or other professional groups can be provided with training television channels, which are inaccessible to other participants. Computer game programs, stock market information, etc. can for selected Participant groups are provided who have the appropriate option code. Computer programs can be written in Microcomputers can be downloaded, data can be sent to printers or facsimile machines, etc. Information cycles can be distributed in broadcasting, but only accessible to those participants who have paid for this service and have stored the corresponding operation code address in their option table memory is.

The designation of the corresponding participants, who can pick up and implement the signals intended for them, is

facilitated by the ability of the network operator to save operating addresses from the central station according to a selective option code for the subscriber (download). There. the company addresses can be changed by the network operator at will, can be provided to each individual participant Services quickly without the need to deploy a maintenance man can be changed, and there is the additional advantage that the - thwarted unauthorized removal of services because the operating code can be changed frequently and at will. This will make the provision of services more flexible and safer thanks to the network operator. · ■

110

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Claims (1)

PATENT CLAIMS yj signal transmission system, characterized by a) a central station (head end), .. b) a transmission medium connected to the central station for the transmission of signals from the central station, c) several participants connected to the transmission medium ~ merstations, '- d) a device in the subscriber stations for reception "and storage of signals from the transmission medium which are indicative of predetermined station addresses, e) a device in the subscriber stations, which the. Have saved station addresses, for receiving and storing the program signals from the transmission medium, which are intended only for those stations which have stored the addresses, f) a facility in the subscriber stations that some of the station addresses for the reception of further signals from the transmission medium and for the Implementation of the further signals, the implementation of depends on the previous storage of the program signals » e 76979-754 Bank account: Deutsche Bank AG Villingen (BLZ 69470039) 146332 EPO-COPY 2. '' Signal transmission system, characterized by. a) a central station, b) a transmission medium connected to the central station . for the transmission of signals from the central station, c) "several subscriber stations connected to the transmission medium, where each subscriber station "contains the following. '(i) "means means for storing a first predetermined one Address code signal, -. (ii) eine'Einrichtung for receiving a second forward "^ 'specific option code signal from the transmission medium and for the storage thereof, (iii) means for receiving and storing a signal that one for the first or second Codes'-ignal has a designating address part, and (iv) a device for converting the last-mentioned signal if the address part matches the first or second "code signal," whereupon the operation of the subscriber station is enabled. 3.. Signal transmission system according to Claim 2, characterized in that. the implementation facility a facility for . the release of the subscriber station to convert further signals into one prescribed by the latter signal Way contains when the subscriber station receives signals that are indicative of the first or second code signal Have address part. 4. Signal transmission system according to claim 3, characterized by a device for receiving and converting signals from the transmission medium that either does not have an address part or one based on the first predetermined code signal ^ limited address 'part-have, as well as d'ie advertisement' of the converted signal. 5. Signal transmission system, characterized by -, a) a central station, - .. ',' b) a transmission medium connected to the central station for the transmission of signals from the central station, c) several subscriber stations connected to the transmission medium, each of which includes the following (i) a first memory device for the permanent storage of a first address design, (ii) a second memory device for storing an operating code signal, (iii) a third memory device for storing a control signal. - (iv) a device for delivering a signal to a Display device, (v) a device for controlling the transmission of a signal sent via the transmission medium to the display device, (vi) a data acquisition circuit for transmitting the operating code signal to the second memory device ■ upon receipt of an operating code signal from the transmission medium, which has an address part matching the address code signal and for storage and transmission a control signal to the third storage device upon receipt of a signal from the transmission medium with an address part and a control signal part that match the operation code signal, and (vii) a processor device for operating the control device in accordance with the control signal at EPO - COPY _.-> ^ "Reception of transmission signals from the transmission medium: ■ -"'- which, due to their nature, can be controlled by the control signal ~ - are ·' ·, with a display signal for the transmission being provided on the display device. ^: - 6.. Signal transmission system according to claim 5, characterized in that that the control device from a television signal folder consists. 7. * Signal transmission system according to claim 5, characterized in that that the control device consists of a television signal channel converter. : 8. Signal transmission system according to claim 5, characterized marked- ■■ indicates that the control device consists of a display generator. : 9. Signal transmission system according to claim 5, characterized in that the control device consists of a television signal folder, a television signal channel converter and a display generator. '■ 10. Signal transmission system according to one of claims 1, 2 or 5, characterized in that the transmission medium is a cable television network. '. ^{; s} * "■ 11. Signal transmission system according to one of claims 1, 2 or 5, ^{characterized,} in that the central station is aus.einer means for producing said signals in asynchronous packets in the HDLC format. 12. Signal transmission system according to one of claims 1, 2 or 5, characterized in that the central station consists of one Large digital signal storage system for storing the signals in a predetermined order from a buffer memory to Saving of continuous character strings of the signals, as well as from a device for the transmission "of the character strings; of the digital signals on the "transmission medium" accordingly this sequence, a television signal source and a device for transmitting the television signals to the transmitter ■: gung'smeäium with the character strings of the digital signals in different frequency bands. ■ '". . 13. Signal transmission system according to one of claims 1, 2 or 5, characterized in that the central station consists of a di- -; Large-scale digital signal storage system for storing the signals in a specific order, a buffer memory for storing them. continuous sequences of these signals and from a device - · j to transmit these digital signal sequences to the transmission ■; medium in the order mentioned, a television signal source and from a device for transmitting the television signals. on the transmission medium, with the digital signal sequences in different Frequency bands. 14. Signal transmission system according to one of claims 1, 2 or 5, characterized in that the central station from a signal source for generating signals for transmission via the over. transmission medium, from a digital signal large storage system for receiving the signals in digital form in a predetermined order and for sequential reading of these signals, from a buffer memory for storing successive character strings of these signals, from a device for transmitting these character strings to the transmission medium in a predetermined Frequency .. band and a device for the transmission of television broadcasts _: signals to the transmission medium in other frequency bands'^& · - consists. ■ 'ί 15 .. subscriber station for connection to a transmission medium for Control of the conversion of signals that are carried by the transmission medium for transmission to a display device, marked by (a) a device for storing information about the transmission medium received conversion control signals that are sent to the subscriber station, ' (b) a device connected to the storage device for converting the signals carried by the transmission medium under the control of the control signals mentioned. EPO.- copy jS # ^J J '■! 16. Subscriber station according to claim 15, characterized in that the conversion device is a folder for organizing the scrambled signals carried by the transmission medium under the control of the said control signals. ■ ■ "'■ " 47. Subscriber station for connection to a transmission medium for controlling the conversion of the signals carried by the transmission medium for transmission to a display device, identified by
-. . (i) a first memory device for permanently storing a first address code signal, (ii) a second memory device for storing an operating code signal,
(iii) a third storage device for storing a Control signal, ·. X'i'v) 'a device for delivering a signal to the display "'""device,
Xy) a device for controlling the transmission of a signal transmitted via ""'' the '"transmission medium to the display 20 device, '()' "a data acquisition circuit for the transmission of the " ^α "'' triVbscodesignals on the second memory device at ¹ ""^;:'Receipt of an operating code signal from the transmission medium ^ ¹ "'" with an address part that ^{matches the address code signal} , ί-_ '' lK "" 'and "' for transmission and storing a control signal ^{L ': L'} 'on the third storage device upon receipt eines.Sig- - "- ■ ^{ir -:'} neck from the transmission medium with a Adressentei'l, the ^un · / 'fits 2To operation code signal and a control signal ^Ali - '"part, and ■ '■ 0 r- γ -, t, - '■ -'. 3 '' a processor device for the operation of the control device according to the control signal on the basis of the reception '· " ^lv - · the' transmission signal from the transmission line, which is controllable by"'"' ■ the control signal ·, a display signal '" being supplied for transmission to the display device t 18. Subscriber station according to claim 17, characterized in that that the control means consists of a television signal channel converter for converting a predetermined display device channel on a television broadcast channel received from the transmission medium under the control of the processor device exists according to the control signal. 19. Subscriber station according to claim 17, marked άααμΓοΙα, that the control device consists of a display generator. to generate an alphanumeric character and / or Structure signal under the control of the processor device exists according to the control signal. 20. Subscriber station according to claim 17, characterized by. (a) a demodulator for connection to the transmission medium for converting the digital signals carried by the transmission medium to baseband, (b) a bus arrangement (c) the data acquisition device with a device to receive the baseband digital signals and to transmit them to the bus arrangement, (d) a memory for logical addresses, which forms the first ■ memory device for the permanent memory The first address code signal which is connected to the bus arrangement, (e) a random access memory containing the second memory ~~ - cheinrichtung forms, for storing the operating code signal as an option table that is connected to the bus arrangement, (f) one to the data acquisition circuit and one to the bus arrangement switched memory with direct access for storing the control signals, EPO - C O P Y ^ - "'(g) an input / output ^ circuit connected to the bus arrangement and has several input and output control connections, (h) a television signal folder with an input for connection to the transmission medium in an input stream " away and an output for connection to the display pre- "-. · direction in an output current path, and with, a control input, which is connected to an output control connection of the input / Output circuit is connected, the folder under control of the control signal with the generation of a Order signal is released by the processor device, which is applied to the input / output circuit will. 21. Subscriber station according to claim 20, characterized by d ^ rch a display generator, which is connected to the bus arrangement, for generating alphanumeric characters and / or • Structure signals under the control of the processor according to the control signal. 22. Subscriber station according to claim 20, characterized by a display generator which is connected to the bus arrangement is to generate alphanumeric character and / or structure signals under the control of the processor accordingly "the control signal" means means for receiving input command signals at an input control output, and a device for generating further alphanumeric characters and / or Structure signals under the control of the processor as a function of the interaction between the command signals and the control signals. 23 subscriber station according to claim 15, characterized in that that the conversion device consists of a microcomputer, which is responsible for the operation using the control signals ., is designed, where the control signals are the associated
Make software. _: ■ 24. Subscriber station according to claim 15, characterized in that that the conversion device consists of a printer. 25. Subscriber station according to claim 15, characterized in that ■ that the conversion device consists of a facsimile display device consists. 26. Subscriber station according to claim 15, characterized in that the conversion device consists of a microcomputer. 27. Subscriber station according to claim 17, characterized in that the control device consists of a microcomputer. 28. Subscriber station according to claim 17, characterized in that ■ that the display device consists of a printer. . ■ ... 29. Subscriber station according to claim 17, characterized in that the control device consists of a facsimile display device consists. EPO-COPY